Spring clutch



Dec. 25, 1934. W. C. STARKEY Y 1,985,387

' sPRiNG CLUTCH I Filed Sept. 9, 1929 mmmp/ Patented Dec. 295, 1934 n i UNITED STATESv PATENTg OFFICE SPRING CLUTCH William Carleton Starkey, Indianapolis, Ind., assignor to L. G. Devices Corporation, Indianapolis, Ind., a corporation oflndiana Application September 9, 1929, Serial No. 391,272 11 Claims. 192-41) My invention is concerned with overrunning consideration o1' the following detailed descripclutches of the typeembodying two co-axial cuption. A p shaped members within which there is disposed The invention consists in the several novel feaa helical spring adapted to permit comparatively tures which are hereinafter set forthiand are free relative rotation of the two clutch members more particularly dened by claims at the con- 5 in one direction but to expand into gripping enclusion hereof. gagement with the interior surfaces of such mem- In the drawing which accompanies4 and forms bers when they tend to rotate relatively in the a part of this specication or disclosure and in other direction. which like numerals of reference denote corre- In order to obtain the most satisfactory operasponding parts throughout the several views: 10 tion for such a clutch, it is necessary to ensure Fig. 1 is a longitudinal section through a device that the helical spring acts throughout itsI entire embodying the invention; Fig. 2 is a fragmental length and that all spring turns are forced out- Section taken on the line 2-2 of Fig. 1; yand wardly when relative rotation of the two clutch Fig. 3 is a longitudinal section through a device l5 members is in such a direction as to unwind or embodying a modiiied form of the invention. l5 expand the spring. For this reason, it has fre- The clutch which forms the subject matter quently been found advantageous to arrange the of the invention 1S adapted primarily for use spring in 'such a manner that its extreme end in connection with a starter drive for an internal turn wi11 bear against its adjacent dutch mcmcombustion engine although it has many other ber with somewhat greater force than will other applicatiOnS. 20 spring-turns. Another expedient which has been As shown in the drawing the clutch comprises used is to employ a friction-brake member which a pair of co-axial cup-shaped clutch members 10 is connected positively to the end spring-turn and and 11 within which is located a helical clutch which is adjustable to provide a frictional drag Sprin8'-12- One of the clutch members, here upon the adjacent clutch member. shown as the clutch member 10, is splined to a 25 Whatever provision has been made for ensurdriving shaft 13, and the other clutch member is ing that the end spring-turn will expand and operatively connected to,asby being integral with, cause all other turns to expand, there is always a driven member in the form of a pinion 14. The Vpresent a certain amount of frictional drag which two clutch members are prevented from moving opposes a free overrunning action and which, on axially relative to each other by means of a 30 account of attendant wear, becomes less and less surrounding tubular casing 15 one end of which effective to accomplish its primary object as the is turned inward to form a iiange 16 overlying clutch is used.- Further, it has always been the a shoulder on the clutch member 10 and the other practice in a simple overrunning clutch to make end of which is provided in its inner surface with the` spring somewhat larger than the recesses an annular groove adapted to receive a split 35 which (receive it; and when this is done, all the spring ring 17 which bears against a shoulder on spring turns exert a frictional drag opposing overthe clutch member 11. running: 'Ihe clutch spring 12 is connected to one of the one object of the present invention is to proclutch members for rotation therewith. As shown 40 vide a coil-spring clutch which is generally an in the drawing, the connection is provided by 4 0 improvement upon, and is more eilicient and posibending axially outward the extreme end 12 oi tive in ,operation than, previously designed the spring 12 and by inserting such extreme end clutches of the same general character by reason in a hole in the inner end of the' recess in the of the fact that it'embodies simple and novel clutch memberlo.

46 means which ensures clutching action of the end. The outer diameter of the spring is less than 45 Spring-turn. without unduly opposing free overthe diameter of the recess in the clutch member runnlng 8Cti0n y 11; sothat in the absence of some special pro- Another object of the invention .is to provide. .vision for expanding the spring thetwo clutch an overrunning clutch 01 the type under conmembers could rotate freely relativetoeach other 'sideration which consists ofbut a small number in either direction. As the clutch is designed 50' ofparts and may be manufactured at a low and to be an over-running clutch and therefore must reasonable 00Steffect a driving connection between the two Other objects oi' the invention and the variclutch members when they tend to rotate relaous advantages and characteristics of the prestively in one direction, there is provided between ent clutch construction will be apparent from a the clutch member 11 and the adjacent end oi the 55 unwind and to expand into spring-turn an interconnecting means which serves to interconnect the end spring-turn and the clutch member when the two clutch members tend to rotate in a direction which would cause the spring to unwind or expand.

In the embodiment of the invention illustrated in Figs. 1 and 2, this interconnecting means comprises a roller 20 which lies between the inner.

surface 21 of the end spring-turn and the outer surface of an annular flange 22 on the clutch member 11. The inner surface 21 of the end spring-turn is made of a spiral conformation of gradually increasing radius toward its extreme end, as is clear from Fig. 2. To retain the roller 20 in place, it may be located in a slot in a sleeve 23 which is rotatable with the clutch member 10.

In Fig. 2, the spring is shown under conditions obtaining when the clutch is at rest, the spring being unstressed and out of engagement with the wall of the recess in the clutch member 11. Should the driving clutch member 10 rotate in the clockwise direction indicated by the arrow in Fig.2, the spring 12 will rotate with it, and the roller 20 will exert a wedging action on the radially inclined surface 21 of the end springturn and will force such end spring-turn outwardly into engagement with the wall of the recess in the member'll. This provides an interconnection between the end spring-turn and the clutch member 11, and causes the spring to gripping engagement with the walls of its associated recess to produce an operative interconnection between the two clutch members. This condition obtains so long as the clutch member 11 is driven from the clutch member 10. v

When overrunning occurs, howeveri. e., when the clutch member 11 rotates in a clockwise direction at a more rapid rate than does the clutch member 10-the roller 20, by reason of its engagement with the flange 22 is carried toward the extreme end of the spring. This permits the end spring-turn to contract out of engagement with the wall of the recess in the clutch member 11 and breaks the operative connection between the end spring-turn and the clutch member 11. This connection being broken, the inherent elasticity of the spring causes all spring-turns to contract, and the clutch member 11 overruns freely. The

only resistance to overrunning is the very slight friction between the flange 22 and the roller 20, which are held lightly in contact with each other by the end spring turn. n

In the embodiment of the invention illustrated in Fig. 3, the interconnection between the end spring-turn and the clutch member 11 is provided by a ball 30 which lies between the end spring-turn and the bottom of the. recess in the clutch member 11. To co-operate properly withl the ball 30, the end spring-turn is bent to provide an inclined surface 31 which recedes from the bottom of the Yrecess in the clutch member 11 toward the end of the spring. The extreme end of the spring may be bent toward the bottom of the recess, as indicated at 32 to retainthe ball in place. The ball rests upon an annular ange which is conveniently provided by the projecting end of a bushing 33 that is rotatable with .the clutch member 11.

The clutch of Fig. 3 operates in a manner analogous to that of Figs. 1 and 2 except that the ball 30 'exerts an axial pressure lbetween the end spring-turn and the clutch member 11, whereas theroll'er 20 exerted a radial pressure on these two parts. When the device is not operative, and

when overrunning is occurring, the ball lies against the bent end 32 of the spring as shown in Fig. 3, the end spring-turn preferably exerting a light pressureholding the ball in contact with the bottom of the recess in the clutch member 11. When the two clutch members tend to rotate in the direction to unwind the spring, the ball 30 exerts a wedging action on the inclined surface 31 and connects the end spring-turn to the clutch member 11. The interconnection which is thus provided between the end spring-turn and the clutch member 11 results in an expansion of the spring into gripping engagement with the walls of its associated recess, thus clutching the two clutch members 10 and'll together. When the clutch member 11 overruns, the ball 30 is moved toward the bent end 32 of the spring to relieve the axial pressure on the end spring-tum and to disconnect such end spring-turn from the clutch member 1l. Thereupon, the spring ls collapsed by its inherent elasticity, and the clutch member 11 overruns freely.

I claim as my invention: A

1. An overrunning clutch comprising two coaxial, relatively rotatable, complemental clutchI members, one of said members being provided with an axial circular recess, a coil spring disposed in said recess and having one end thereof operatively .connected to the other of said members so as to rotate therewith, said spring having a normal diameter less than that of the recess and being normally free from operative connection with the recessed clutch member, and means operable in response'to relative rotation of the two clutch members in the direction tending to unwind the spring for exerting a wedging action in a radial direction on the other end ofthe spring in order operatively to connect said other end of the spring andthe recessed clutch member.

2. An overrunning clutch comprising two relatively rotatable co-axial members, one of said members being provided with an axial circular recess, a coil spring located in said recess and operatively connected to the other of said members, said spring having a. diameter less than that of the associated recess and being normally free from operative connection with said recessed member, said recessed member and the end turn of said spring being provided with adjacent surfaces inclined relatively to each other and a circular ypart located between said inclined surfaces and adapted to exert a wedging action upon them to connect operatively said recessed member and the adjacent end of the spring when the two members tend to rotate relatively in a direction to expand said spring.

3. An overrunning lclutch comprising two relatively rotatable co-axial members, one of said members being provided with an axial circular recess,a coil spring located in said recess and operatively connected to the other of said members, said spring having a diameter less than that of the associated recess and being normally free from operative connection with said recessed member, said recessed member and the end turn of said spring being provided with adjacent surfaces inclined relatively to 'each other, a circular part located between said inclined surfaces and adapted to exert a wedging action upon them to connect operatively said recessed member and the adjacent end of the spring when the two members tend to rotate relatively in a direction to expand said spring, and means rotatable with said spring for limiting movement of said circular part.

4. An overrunning clutch. comprising two relatively rotatable co-axial members, one of said members being provided with' an axial circular recess, a coil spring located in said recess and operatively connected to the other of said members, said spring having a diameter less than that of the associated recess and being normally free from operative connection with said recessed member, said recessed member andl the end turn of said spring being provided with adjacent surfaces inclined relatively to each other, a circular part located between said inclined surfaces and adapted to exert a wedging action upon them to connect operatively said recessed member and the adjacent end of the spring when the two members tend to rotate relatively in a direction to expand said spring, and means for limiting movement of said circular part. I

5. An overrunning clutch comprising two relatively rotatable co-axial members, one of said members being provided with an axial circular recess, a coil spring located in said recess and operatively 'connected to the other of said members, and means exerting a rolling wedging action on the end turn of said spring for operatively connecting said recessed member to the adjacentend of said spring when the two members tend to rotate relatively Iin a direction to unwind said spring.r

6. An overrunning clutch comprising tworelatively rotatable co-axal members, `one of said members being provided with an axial circular recess, a coil spring located in said recess and operatively connected to the other of said members, said recessed member and the end turn of said spring being provided with adjacent surfaces inclined relatively to each other, and a circular part located between said inclined surfaces and adapted to exert a wedging action upon them to connect operatively said recessed member and the adjacent end of the spring whenl the two mem- -bers tend to rotate relatively in a direction to expand said spring.

'7. In an overrunning clutch of the character described, the combination of two relatively rotatable members, a coil spring having one end turn normally free lfrom connection with one of said members whereby said two members may normally rotate relatively to one another in either direction, said members having surfaces arranged to be gripped by said coil spring upon a change in its diameter, and means exerting a rolling wedging action on said end turn of the spring for operatively connecting the same to one of said members when said members rotate relatively toone another in one direction.

8. In an overrunning clutch of the character described, the combination of two relatively rotatable axial members coacting to provide a clutch spring recess having an internals/clutch surface, a coil spring in said recess and having one end turn normally free from connection with one of said members whereby said two members may normally rotate relatively to one another in either direction, and means actuated in response to relative rotation of said members in one direction and operating with a rolling wedging action upon said end turn of the spring operatively to expand and engage the same, against said internal clutch surface.

9. In an overrunning clutch of the character described, the combination of two relatively rotatable members, a coil spring having one end turn normally free fromk connection with one of said memberswhereby said two members may normally rotate relatively to one another in either direction, said members having surfaces arranged to be gripped by saidcoil spring upon a change in its diameter, and a rolling element extending between and engaging said end turn of `the spring and an adjacent part of said one member and acting with a rolling wedging action in response l to relative rotation of said members in one direction for connecting said end turn to said one member.

` l0. An overrunning clutch comprising two relatively rotatable members coacting to provide a clutch spring receiving `recess, a clutch spring located in said recess, means operatively connecting one endturn of said spring to one of said members, the other of said members having a surface adapted to be engaged by said spring upon a change in its diameter in one direction, andv means operating in response to relative rotation of said members in one direction for exerting a.

rolling wedging action upon the other end turnvof the spring for operatively engaging the same with said surface.

11. An overrunning clutch comprising two relatively rotatable members coacting to provide an annular recess having an internal surface, a clutch spring in said recess. having a normal clearance with respect to said surface, means operatively" connecting one end turn of the spring to one of said members, and means operating in response to relative rotation of said members in one direction for exerting a rolling wedging action on the other end turn of the spring for radially expanding the same into operative engagement with said internal surface. WILLIAM CRLETON STARKEY. 

